The present invention generally relates to power machines such as front end loaders and skid steer loaders. More specifically, the present invention relates to a load bearing pivot assembly for connecting a boom arm of a power machine to the main frame or an implement (e.g., adapter plate) or both.
Power machines, such as front end loaders and skid steer loaders, typically have a main frame which supports a cab or an operator compartment and a movable boom arm which, in turn, supports an implement. The implement is typically an adapter plate capable of releasable connection to an attachment such as a bucket or an attachment requiring pressurized hydraulic fluid for operation such as an auger, a snowblower, a stump grinder, a hydraulic breaker, or the like. The movable boom arm is pivotally coupled to the main frame of the power machine and is powered by power actuators which are commonly hydraulic cylinders. In addition, the attachment coupled to the implement (i.e. the adapter plate) is typically powered by one or more additional power actuators which are also commonly hydraulic cylinders. An operator manipulating such a power machine raises and lowers the boom arm, and manipulates the attachment, by actuating the hydraulic cylinders coupled to the boom arm, and the hydraulic cylinders coupled to the attachment.
An attachment requiring pressurized hydraulic fluid for operation typically receives the hydraulic fluid through hydraulic lines or hoses. The hydraulic lines are routed along the boom arm to the distal end of the boom arm where a connection is made to the attachment. Quick couplers may be mounted to the hydraulic lines for quick connection to the attachment. However, routing the pressurized hydraulic lines along the boom arm to the attachment renders the hydraulic lines susceptible to failure due to repeated flexure and due to exposure to the surrounding abusive environment.
The present invention provides an improved load bearing pivot assembly for connecting the boom arm of a power machine such as a front end loader to the main frame, or the implement (e.g., adapter plate) or both. The load bearing pivot assembly provides a fluid path therethrough in order to eliminate fluid lines at the pivot point which are otherwise susceptible to failure due to repeated flexure and due to being exposed to an abusive environment.
In one embodiment of the present invention, a power machine having a boom arm and an implement (e.g., an adapter plate) is provided with a load bearing pivot assembly for pivotally connecting the implement to the distal end of the boom arm. The pivot assembly includes a two portions, one connected to the boom and the other connected to the implement. Each portion has a fluid path which are in fluid communication with each other. The fluid paths eliminate the need for a fluid line (e.g., a hose) at the pivot point which would otherwise be exposed to continuous bending.
Both portions of the pivot assembly preferably include a coupler for connection to a fluid line. One of the fluid lines is connected to a source of pressurized hydraulic fluid and the other line is adapted for connection to an attachment requiring pressurized hydraulic fluid for operation. Such attachments include, but are not limited to, grapples, augers, tree spades, jack hammers, etc. The fluid lines are preferably at least partially contained within the boom and/or the implement to protect the lines from exposure to the abusive environment.
The fluid line that is adapted for connection to an attachment may be connected to a movable (e.g. slidable, rotatable) block mounted on the implement. The movable block includes a coupler for releasable connection to the attachment. With this arrangement, a connection to the attachment may be accomplished by maneuvering the implement and block with the loader rather than by manually connecting the line to the attachment.
One of the portions of the pivot assembly preferably comprises a pin. The other portion of the pivot assembly preferably comprises an annular bearing surrounding the pin. The pin may include an annular recess, a lateral channel and a longitudinal channel which comprise a fluid path. The annular bearing may include a gap which comprises another fluid path in fluid communication with the fluid path of the pin. The bearing preferably includes a bearing surface which is lubricated by the fluids in the fluid paths.
In another embodiment of the present invention, a power machine having two boom arms and an implement (e.g., an adapter plate) is provided with two load bearing pivot assemblies, one for pivotally connecting each boom arm to the implement. Each pivot assembly includes a fluid path therethrough. The fluid paths eliminate the need for fluid lines (e.g., hoses) at the pivot points which would otherwise be exposed to continuous bending.
In yet another embodiment of the present invention, a power machine having a main frame assembly and a boom arm includes a load bearing pivot assembly for pivotally connecting the main frame to the proximal end of the boom arm. The pivot assembly includes a fluid path defined therethrough. The pivot assembly preferably includes a pin and an annular bearing surrounding the pin. The pin may include an annular recess, a lateral channel and a longitudinal channel which comprise a fluid path. The annular bearing may include a gap which comprises another fluid path in fluid communication with the fluid path of the pin. The bearing preferably includes a bearing surface which is lubricated by the fluid in the fluid paths.